Linear Technology Hydraulic steel structures
Locks, gates and water-engineering infrastructure: high loads, long service life and formal documentation.
View industry →Knowledge · Heavy-duty
Heavy-duty electric actuators for high forces and rough operating conditions
High continuous forces, long strokes, water, heat or corrosion: heavy-duty applications do not begin at a force figure but at the load case. This page brings together the key technical questions – parameters, applications and limits – and shows from real references how S+R designs heavy, customer-specific electric actuators.
In brief
Heavy-duty begins with the load case, not with a force figure. Single electric actuators reach about 500 kN in special builds; higher total forces are achieved with several synchronised cylinders. What is decisive is force, stroke, environment, corrosion, service access and safety – together with calculation and documentation that hold up over years. S+R designs from the load case outwards and checks the technical feasibility instead of making blanket promises.
Classification
When do we speak of heavy-duty applications?
There is no fixed kN threshold. Heavy-duty is the combination of high continuous force, long stroke, rough environment and a long required service life – frequently with formal documentation.
A high force alone does not make a heavy-duty task. Only when large forces have to be transmitted safely over long strokes, under water, heat, dust or corrosion and over many years of operation does the design become a discipline of its own: screw, bearings, guidance, mounting, protection class and safety margins are derived together from the load case – and documented so that operation, maintenance and warranty hold up.
Sizing
Which parameters matter for heavy-duty work.
You don't need to know every point exactly. Even a rough figure per line helps S+R narrow down margins, protection class and design.
Force
The governing pushing or pulling force in the load case. Single cylinders reach about 500 kN in special builds; higher total forces are achieved with several synchronised cylinders.
Stroke
Long travel increases buckling load and the need for guidance – the mechanical design grows more important as the stroke increases.
Speed
Usually low for heavy-duty work. Speed, load and duty cycle together decide the screw and the drive.
Load case
Pushing or pulling, static or dynamic, with shock loads. S+R designs from the load case outwards – not backwards from a standard size.
Duty cycle
Cycles per hour or duty-cycle percentage determine heat, screw selection and service life. Realistic figures matter more here than a wished-for value.
Lateral and side forces
Lateral forces belong in the guidance and mounting, not in the screw. For heavy-duty work, their clean absorption is decisive for service life.
Environment
Outdoors, water, heat, dust or slag determine the material, protection class, bellows and sealing concept.
Corrosion
Corrosion protection for wet, outdoor and salt environments belongs in material choice, coating and sealing – designed in, not retrofitted.
Temperature
Operating and ambient temperature affect lubrication, seals and, where present, the electronics.
Service access
Maintenance window, removal path and reachability on the structure – considered early so that servicing and replacement remain possible later.
Safety requirements
End-position monitoring, safety limit switch, overload protection and safety margins according to application and standard.
In practice
Typical applications.
Heavy electric actuators work where high forces meet rough conditions and a long service life.
Locks
Heavy, permanently safe positioning movements under water and weather influence – often over decades.
Bridges
Movable bridges with high forces, outdoor operation and reliable end-position monitoring.
Foundry & steelworks
Heat, dust, slag and high continuous forces – robust, heat-resistant linear actuators.
View industry →Test benches
Reproducible high forces and load cycles with defined position and data connection.
View industry →Special machinery
Heavy positioning and pressing tasks in special machines, designed for the specific load case.
Special build
Why standard cylinders often fall short.
Standard sizes cover a great deal. Heavy-duty work, a rough environment and a long service life with documentation, however, require a customer-specific design – in three places.
Sizing & margins
High continuous forces, long strokes and shock loads call for larger screws, bearings and safety margins instead of a tight catalogue design.
Protection & corrosion
Outdoors, moisture, heat and dust demand material choice, corrosion protection, bellows and overload protection – designed in, not retrofitted.
Documentation & maintainability
Calculation, interfaces, tests and service access are documented so that operation, maintenance and warranty hold up over years.
Design principle
AP, SP and XP as technical starting points.
The three design principles are a proven starting point, not a rigid programme – the heavy-duty design takes shape from them individually.
AP
Axial, direct force line with high force density and good service access – the robust basis for high forces.
SP
Parallel or angular mounting for short installed lengths when installation space is tight.
XP
Enclosed design with integrable overload protection – protected against dirt, moisture and harsh outdoor conditions.
References
Heavy-duty in practice.
Four real projects – from the lock installation to rough steelworks operation.
Heavy-duty lock drive
For a large lock installation, 22 heavy electric actuators move loads in the range of around 1.000 kN together – designed from the load case, documented and maintainable.
View reference →Bridge drive
Four electric actuators of around 350 kN each move two movable bridges – designed for outdoor operation, reliable end-position monitoring and long-term maintainability.
View reference →Heavy-duty custom actuator
A robust electric cylinder replaces a maintenance-intensive adjustment in rough plant operation – electrically controllable, with a matching interface and documented service points.
View reference →Lock actuator after 20 years
A heavy-duty cylinder comes back after around 20 years – repairable, maintainable and technically traceable thanks to retained product knowledge.
View reference →FAQ
Common questions about heavy-duty.
Up to what force does S+R build electric actuators?
The standard sizes cover the range up to about 500 kN; in special builds also beyond that as a customer-specific design. Very high total forces are achieved with several synchronised cylinders – as in the lock drive with around 1.000 kN across 22 cylinders.
When is an application considered "heavy-duty"?
There is no fixed kN threshold. What matters is the combination of high continuous force, long stroke, rough environment and a long required service life – together with documentation and maintainability.
Are electric cylinders suitable for hydraulic steel structures and outdoor use?
Yes. With the right material, corrosion protection, protection class and documented interface they are designed for locks, bridges and water engineering – including a service concept over years.
What happens to lateral and side forces?
Lateral forces belong in the guidance and mounting, not in the screw. For heavy-duty work the mechanical absorption is designed early so that screw and bearings are protected.
What are the next steps after the inquiry?
Describe the load case roughly – force, stroke, environment, duty cycle and safety needs. S+R checks the technical feasibility, calculates margins and safety factor and proposes a sound design.
Describe the load case roughly – S+R checks the technical feasibility.
Force, stroke, environment, duty cycle and safety needs in keywords are enough. S+R calculates margins and safety factor, classifies the design principle and gets back to you with a sound assessment – without blanket promises.